The present invention relates to a dot matrix display comprising a semiconductor light emitting element array or a liquid crystal display whose pixels (picture elements) are arrayed in matrix form for displaying the desired characters, numerals, graphics, and the like. More particularly, the invention relates to a dot matrix display in which the data transfer between the modules is simplified in the case of constituting a large display by arraying the dot matrix modules having matrix pixels (picture elements), in vertical and/or horizontal direction.
For example, in displaying a starting/arriving time guide in railway station by using a semiconductor light emitting diode (hereinafter to be referred to as LED), display is required to be made in large characters as large display size so as to allow the visitors to view the contents from a distant location. For this purpose, for example, the dot matrix modules formed by arraying for example LED in matrix form of 16xc3x9716 or 24xc3x9724, are arrayed in a lateral direction and/or vertical direction, and are used to make display of one Japanese character by each module, and thus a display of for example xe2x80x9cFIRST START, SPECIAL EXPRESS, TIME 00:00, LINE 1xe2x80x9d is made by the whole modules.
In such a dot matrix display, for example, if the data to be displayed are inputted in the respective ones of the modules arrayed in a lateral direction, very large number of wiring lines are to be employed. Therefore, there is adopted a system to send in the display data as serial data from the module at the end and transfer the data to each adjacent module. Because of this, for example, as the reverse side of a part of the module 20 is shown in FIG. 5, the modules 20 are connected with means called wire harness 26 which is made by bundling wires in a plate form with nylon or the like, to make it possible to transfer the data.
In FIG. 5, the numeral 20 shows a dot matrix module, and 21 shows a lamp type LED constituting each dot (pixel), being fixed to the LED substrate 23 at its package part, with the lead connected to the display section substrate 24 through the through-hole and fixed. A part of the lead of LED 21 is further connected to the control substrate 22 through the through-hole of the control substrate 22 and fixed. On the reverse side of the control substrate 22 (upper part in the drawing), though not illustrated, there are wiring for driving each module, IC such as RAM for temporarily recording the data to be displayed, and shift register are provided and connected with the connectors 25. And, in order to input the data to be displayed in the IC of each module 20 or to make control for changing over the display, connection is made between the modules 20 by the wire harness 26 made by bundling wires, so that, as described above, the data are to be successively transmitted from the end module 20. The data to be transmitted between the modules 20 include the serial data for display, clock signal, address signal, functional signal, etc., and the number of wires is about 10.
In the conventional dot matrix display, as described above, the modules are connected by the wire harness, but because the number of modules is about 20-400, there is a problem to require longer time for connection according to the increase in number.
Furthermore, because the connection between the modules is made simply by inserting a wire harness into the connector, there is a problem that the modules tend to come out from the connector by vibration or the like, to cause defective display during use, thereby leading to loss of reliability.
The present invention has been made to solve the problems as above, and its object is to provide a highly reliable dot matrix display which is free from the trouble of work of connecting the leads comprising the wire harness and the like between the dot matrix modules to be displayed in parallel arrangements, and which does not show disconnection even in case of occurrence of vibration.
The dot matrix display according to the present invention comprises a plurality of parallel arrangements of the dot matrix modules which have a luminous section (dot, pixel or picture element) provided in matrix form, a drive section for controlling the ON and OFF of the luminous section, and a signal transmission section for transmitting and receiving the display signal for controlling the ON and OFF to the drive section, the signal transmission section comprises a light emitting element and a light receiving element, and the light emitting element and the light receiving element are provided on the respective module in opposed manner between the adjacent modules.
The drive section herein means the portion constituted by a control section for controlling the display contents as data and a drive circuit for driving LED. Also, the display signal means the signal for writing in the control section and displaying such as serial data of the display contents, clock signal, address signal, signal for defining address, signal for writing in memory, etc.
By adopting this constitution, it becomes unnecessary to connect wires between the modules, and the display signal can be transmitted by light. Because of this, there can be obtained a dot matrix display which is easily assembled, and is free from generating defective display even under vibration or the like.
Due to the provision of a plurality of the light emitting elements and light receiving elements in parallel arrangements on each module with separation of the areas between the adjacent light emitting elements or light receiving elements by the light shielding walls, respectively, no signal mixing occurs between the adjacent light receiving elements or no erroneous operation occurs by entry of external light, and desirable state is obtained.
It is possible for the signal transmission section to send and receive the display signal according to the putting on or putting off of the light emitting element proportionate to the high and low condition.
Due to the formation of the luminous section by the semiconductor light emitting element, e.g. lamp type light emitting diode or chip type light emitting diode, a dot matrix display by light emitting element is obtainable, and by formation of each dot by the pixel of the liquid crystal display module, a dot matrix display by liquid crystal display element. The chip type light emitting diode includes the light emitting diodes formed by showing flat type illumination through direct mounting of the LED chip on the display substrate or by mounting of the LED chip on the insulated substrate.